Thompson declined a full interview with Visalia Times-Delta but said she had no idea of the crimes her brother is accused of committing.

Her voice quivered as she opened the door to speak and make eye contact.

“We are very sympathetic to the victims and their families,” she said as tears ran down her face.

Thompson met with her pastor Thursday evening, trying to find comfort and answers.

She may be left in the dark, along with many others who want to know what led the man to a life of crime. Some of DeAngelo's family still lives in Exeter.

His mother died in 2010 in Exeter, where she's buried.

A family friend said DeAngelo's sister and family are struggling to comprehend the news.

For DeAngelo, the fight has just begun.

He will be in court for the first time Friday where he faces murder charges.

Joseph DeAngelo(Photo: Sacramento Sheriff's Department)

Genealogy guides detectives

For decades, investigators had the DNA of the killer. But they couldn't track him until genealogy lent a hand.

Investigators plugged in DNA from one of the crime scenes to a genealogy website used to find relatives and learn more about their background. From there, officials followed family trees to try and narrow down a suspect.

Eventually, that led to DeAngelo, a former Exeter police officer.

Sacramento's Chief Deputy Steve Grippi confirmed the use of a genealogy website to USA TODAY but declined to elaborate on what website was used.

"We have given you as much information as we can at this time," Grippi said.

The Sacramento Bee reports investigators narrowed down potential suspects on the genealogy websites and soon DeAngelo became their primary target. He lived in the areas where the crimes happened and fit the right age range.

It's possible Tulare County was the first among a bloody and violent trail of locations that DeAngelo is suspected of instilling fear.

Sources close to the investigation said police rummaged through DeAngelo's trash to gather DNA samples.

It all came together after investigators obtained discarded DNA that matched DeAngelo. It was a match for other samples taken from the decades-old crime scenes.

While no DNA was gathered at the Visalia crime scene of Claude Snelling, who died at the hands of the Visalia Ransacker, detectives believe DeAngelo is one and the same.

Officers surveilled him for six days and arrested him outside his Sacramento area home. Neighbors say they had just seen him outside building a table before the FBI and Sacramento law enforcement pounced.

Ancestry.com, one of the more popular websites used to track family history and reconnect with relatives, said it was unaware of the investigation.

"We have not been in contact with law enforcement regarding the Joseph James DeAngelo case," a spokesperson told USA TODAY. "Ancestry advocates for its members’ privacy and will not share any information with law enforcement unless compelled to by valid legal process."

But it appears as though law enforcement used the software like any member would have and simply shared DeAngelo's DNA to the website.

DeAngelo, a Navy veteran and native of New York, has been charged in eight homicides. Investigators are still working to link him to the other crimes, including 12 deaths, 50-plus rapes and the ransacking of more than 100 homes in the Visalia area.

Man was known as East Area Rapist, Golden State Killer and most notoriously the Original Night Stalker. He started his criminal career in Visalia.(Photo: Visalia Times-Delta)